A chronic clinical scalp condition with the same etiology as seborrheic dermatitis, but considered to be a milder form. Dandruff is most commonly associated with oily white flakes in hair and on the scalp. Other symptoms include itching, scalp tightness and scalp dryness. Dandruff can be effectively treated with over-the-counter anti-dandruff shampoos and conditioners, such as those containing pyrithione zinc (PTZ). Approximately 50% of the population experiences dandruff or seborrheic dermatitis.